Reichhelm, Feenstra Kuiper, Di Felice and La Grande Storia degli Scacchi all give Dion M. Martinez. Kingston, in reviewing The Steinitz Papers by Landsberger, gives Aristide Martínez, but it is clear from Landsberger's book that this was the Philadelphia Martinez (Dion M.), not the New York Martinez (Aristide). Elo gives a combined result of 21.5-3.5 for Steinitz over the years 1882-1883, which matches other sources that give +7-0=0 and +3-1=3 in 1882 and +9-0=2 in 1883 for a total of 21.5-3.5.